Motor controlling apparatus



Feb. 9, 1932. w, wYMAN 1,844,834

MOTOR CONTROLLING APPARATUS Filed Jan. 2, 1929 5 Sheets-Sheet 1 Au /4Mawry.

Feb. 9, 1932. c. w. WYMAN MOTOR CONTROLLING APPARATUS 3 Sheets-Sheet 2Filed Jan. 2, 1929 7 1522262392 /zariea' 5M Zq'yman.

Feb. 9, 1932. c. w. WYMAN MOTOR CONTROLLING APPARATUS Filed Jan. 2, 192915 Sheets-Sheet 3 Patented Feb. 9, 1932 UNITED STATES PATENT OFFICECHARLES W. WYMAN, OF CLAREMONT, NEW HAMPSHIRE, ASSIGNOR TO SULLIVANMACHINERY COMPANY, A CORPORATION OF MASSACHUSETTS MOTOR CONTROLLINGAPPARATUS Application filed January 2, 1929. Serial No. 329,929.

My invention relates to motor controlling apparatus.

The general object of my invention is to provide improved means forcontroll ng reversible motors. It is a primary ob ect to provideimproved controllin apparatus for electric driving motors involvingimproved interlocking mechanism for a reverse sw tch, preventingreversal of the latter at times when such reversal would result in thebreaking at the reverse switch contacts of circuits through whichsubstantial currents are flowing. Particularly when automaticallycontrolled starting resistance cutting out systems are employed is therea likelihood of the interrupting of large currents at the reverse switchcontacts unless safety devices are provided, for should a contactorstick the reverse switch might be called upon to interrupt the full linecurrent, which might result in short-circuiting the reverse switch andburning up of the latter. It is an object of my invention to provideimproved means for preventing operation of the reverse switch under suchconditions. It is a still further object of the invention to provideimproved interlocking mechanism for the reverse switch controlled by anelectro-magnet connected in such a mannerthat the regenerative currentpresent due to the continued rotation of the motor cannot be broken atthe reverse switch contacts. In an approved form the reverse switch lockmagnet may be connected directly across the armature. A still furtherobject of the invention is to provide an improved locking device for acommon operating element for both a reverse switch and a pilot switchwhich controls automatic controlling apparatus located at a point remotefrom the reverse switch, this improved locking device operating, whilecurrentflow in the motor continues, to prevent movement ofthecontrolling element to a position effecting reversal of current inthe motor while permitting sufiicient movement to efiect control of thepilot switch. Still another object of the invention is to provideimproved means for preventing reversal of the motor while the latter isrunning at generating speeds.

Other objects and advantages of my inven tion will appear during thecourse of the following specification and claims.

In the accompanying drawings I have shown for purposes of illustrationone form which my invention may assume in practice.

In these drawings,-

Fig. 1 represents a view generally in plan, the machine casing beingbroken away to show the illustrative embodimentof my improved reverseswitch and controlling elements.

Fig. 2 is a central vertical section through the illustrative embodimentof my improved reverse switch and interlock, on line 22 of Fig. 1.

Fig. 3 is a transverse section through the machine casing on line 3-3 ofFig. 2, show ing the illustrative embodiment of my improved reverseswitch interlock in elevation.

Figs. 4, 5 and 6 are diagrammatic views of the illustrative embodimentof the reverse switch and associated elements, the reverse switch beingshown in its different positions.

Fig. 7 is a wiring diagram illustrating the illustrative embodiment ofmy improved reverse switch and interlock as connected to a controllingapparatus located at a point remote from the motor.

In a preferred form of my invention I have provided a reverse switch ofrugged construction having an operating element which when moved ineither direction from a neutral position automatically closes a pilotswitch. This pilot switch closes a control circuit for automaticcontrolling apparatus located at a point remotefrom the motor, operatingto place the motor across the line through resistance and gradually cutout the resistance. A movable plunger is arranged adjacent the commoncontrol element for the reverseswitch and pilot switch and is actuatedby an electromagnet into interlocking relationship with the controllingelement when said magnet is energized. This interlock while permitting alimited movement of the controlling element, sufficient to enable changein position of the pilot switch, prevents suflicient movement toseparate the reverse switch contacts until the electromagnet isdeenergized. The coil of this magnet r material such as bakelite or hardrubber.

is connected directly across the armature terminals so that the magnetis energized until the motor comes nearly to a standstill because of thevoltagegenerated in the armature rotating in the self generated magneticfield. /V hen the motor comes to a standstill this interlockautomatically releases, permitting the reverse switch to be moved to itsopposite position for effecting reversal of the motor.

In the specific embodiment of my invention illustrated in the drawings Ihave shown a machine frame 8 in which may be mounted a control shaft 9extending into the interior of the casing and having on its operatingend outside the casing a manual controlling element 10. Reverse switchmechanism is at tached to the machine casing by means of a suitablebracket 11 and bolts 12. This bracket has a vertically projectingportion 13 which provides a recess 14 forming a housing for a part ofthe movable switch act-uatingelement '15. A bearing plug 16 fixed to thestationary bracket projects into a recess 16 in the movable member 15,and a spring 17 mounted between said plug and recess acts against themovable element 15 to hold the movable contacts of the reverse switch inengagement with the stationary contacts. This switch carrying element 15may be constructed of any suitable insulating A pair of arcuate movableswitch elements 18 and 19 of conducting material are loosely connectedto member 15 by small lugs 20 and 21 projecting into recesses 22 and 23respectively in member 15. The stationary contacts of the reverse switchare secured to a stationary plate 24 of insulating material byintermediate member29 which, together with stationary plate 24, forms ahousing for the reverse switch. The plate 24 and member 29 are securedto the upstanding portion 13 of the bracket 11 by any suitable meanssuch as bolts 46. A gear 30 is formed integral with the switch carryingmember 15 and is adapt ed to mesh with a pinion 31 on the operatingshaft 9. It is'of course not necessary to have the teeth in gear 30extending completely around the periphery of the member15, since only asegment of the gear will ever be brought into mesh with the operatingpinion.

In Fig. 1 particular attention is directed to the manner in which theoperating handle 10 is mounted on the control shaft. A key 32' connectsthe handle to the shaft so as to prevent relative rotation but permit alimited amount of longitudinal sliding movement. On the exterior surfaceof the hub ofhandle 10 there are formed a plurality of grooves 33 and 34connected by a longitudinal groove 35, and a stationary pin 36 suitablymounted on the frame of the machine engages in the grooves so as toprevent rotation beyond the central or neutral position without a pauseto slide the handle longitudinallyot the shaft.

My improved interlocking mechanism for the reverse switch will now bedescribed. As est shown in Figs. 2 and 3, the switchactuating element 15has formed therein a pair of arcuate recesses 37 and 38 either of whichis adapted to receive the end of a lockingplunger 39. An electromagnethaving a coil 40 housed in a casing 41 is fixed directly to the bracketby means of a threaded stud A movable armature 43 is mounted on thecasing 41 and directly connected toplunger 39by a nut 44.

A spring 45 normally holds the armature 43 and plunger in the retractedposition, as shown in Fig. 2, where they will. not interfere withoperationof the switch actuating member 15. However, when the coil 40 ofthe electromagnet is energized, the armature will be attracted and theend of plunger 39 will engage in recess 37 or 38, depending on theposition of the reverse switch, and control the movement of the switchactuating element as will presently appear. For the purpose ofpreventing accidental displacement of the switch actuating element 15from either-of its on positions, there is provided a small plunger 47having a conical head adapted to engage in conical recesses in theswitch actuatingelement and resiliently held in engagement with theserecesses by a spring 48.

The switch for controlling the pilot circuit of the remote controllingapparatus as before stated is arranged to be actuated by the sameoperating element as the reverse switch and is herein shown in Fig. 3 at49. Theterminals which connect to the pilot circuit are indicated at50.and 51, the switch 49 being piv- .otally connected to one of theseterminals and normally held open by spring 52. The lower side of switch49 rests on the teeth of gear 30 and as indicated In dotted lines inFig. 3, a

a number of these teeth are cut away to for an arcuate portion 53 ofreduced radius which will permit control switch 49 to drop to openposition when the reverse switch operating element is in neutralposition or within a certain predetermined angle at either side ofneutral position.

Attention is now directed to the diagrams shown in Figs. 4, 5, and 6.Fig. 4 shows the reverse switch in neutral position. A pair ofstationary contacts 54 and 55 diagonally opposite each other connect topower lines 56 and 57 respectively. The other pair'of stat onarycontacts 58 and 59, also arranged diagonally opposite each other andmidway between contacts 54 and 55, connect to the armature by means ofwires 60 and 61 respectively, the armature being indicatedat 62.

In Fig; 4 the movable contacts 18 and 19 engage only the pair ofcontacts 54 and 55 connected to the power lines and therefore the tion.The movable switch elements 18 and 19 are touching only the pair ofstationarv contacts connected to the power lines and the pilot switch 49is in open position, resting on the cutaway portion 53 of the gear 30.The operator now manipulates the control handle in one direction or theother, depending on the direction of motor rotation which he desires,and the stationary pin 36 engages in groove 33 or 34. Assume that theoperating element is turned so as to bring the movable contacts in theposition shown in Fig. 5. The control circuit switch 49 has moved toclosed position due to engagement with full length teeth on gear 30, andrecess 37 is in positionpermitting engagement with plunger 39. Duringopposite direction of motor rotation the plates 18 and 19 are in thepositions indicated in Fig. 6 and plunger 39 engages in recess 38. Thepilot switch 49 is automatically closed on turning the reverse switchmember in either direction to effect either direction of motor rotation.Now if the operator attempts to move the switch from the position ofFig. 5 to the position of Fig. 6 or vice versa, the length of recesses37, 38 is such as to permit only a limited movement sufiicient to causeopening of the control switch but not sufiicient to break the maincircuit, until the plunger 39 is retracted by its spring 45.

Referring now to thewiring diagram of Fig. 7, the units located at themachine are illustrated in the left hand portion of the figure and allthe equipment in the right hand part of the figure may be located at anyconvenient remote point as in the entry of a mine and connected to theunits on the machine by only three wires, as ina cable 85. Thisautomatic remote control system is described in detail in my copendingapplication Serial No. 243,964. filed Dec. 31, 1927, and will be hereindescribed as briefly as possible, and if a more detailed description isdesired, reference may be had to the aforesaid application. The motor inthis figure is indicated at 62 and it will be noted that coil of theelectromagnet is connected directly across the armature terminals by apair of wires 63 and 64. The series field is indicated at 65 and theshunt field at 66, the reverse switch being indicated diagrammaticallyat 67 and the pilot switch at 49. The equipment included in theautomatic controlling apparatus located at a point remote from themachine includes a plurality of resistance controlling contactors 68,69, 70, and 71 and also a plurality of contactor controlling relays 72,73, and 74. The resistance unit controlled by the contactors comprisesin this instance three sections 75, 76, 77. An overload switch 78 isadapted open the control circuit whenever there is an overload on themotor. In operation, the coil. of relay 72 is immediately energized whenthe reverse switch is turned suiiiciently to close a circuit, but notfar enough to close the pilot switch, by power from the minus side ofthe line through reverse sw ch 67, meter 62, series field 65, line 79,through all the resistance units, lines 80, 81 and hack to the positiveside of the line through lines 82, 83, 84. Upon closure of pilot switch49, the holding coil for the first contactor 63 is energized by powerfrom the minus side of the line through switch 49, pilot wire and line86 and back to the positive side of the line through lines 87, 88, 89,90. Closing of the first contactor 68 shortcircuits the coil or relay72, allowing the same to close a circuit after a certain interval oftime required for the current to die out in relay 72, and power flowsfrom pilot wire 85 through wire 91, relay 72, line and energizes thecoil of relay 69, the cir' t being completed to the positive side of theli .e through wires 93, 88, 89, and 90. At the time of closing of thefirst contactor 68, the holding coil for relay 73 was energized by thevoltage drop across section 77 of the resistance through lines 94, 95and 80. When the second contactor 69 closes, the first p on of theresistance is cut out and at the same time the holding coil for relay 7is short circuited, thereby allowing the same to close after a certaintime interval required for the current to die out in the relay coil. Ina similar manner contactors 70 and 71 are closed in turn and the motorplaced directly on the line by the last contactor 71. At the time ofclosing of this contactor a switch 96 in the control circuit is opened,thereby deenern ing the holding coils for the first three c actors.However, the last contactor is kept energized by power from the pilotwire through relays 7 2 and 74.

In my copending application Ser. No. 243,964 above referred to, I arepresenting claims to an electric motor contl system including a motor,main power lines leading thereto, an adjustable resistance, andapparatus for connecting the motor to the power lines through theresistance and for gradually cutting out the resistance the motor comesup to speed, which apparatus comprises a plurality of switches, andelectromagnetic means for operating them in a predetermined sequencc, acontrol circuit for supplying current to the elcctro-magnetic means, andmechanical means for automatically breaking the circuit through all theelectromagnetic means except the one for operating the last switchwhenthe last switch element, due to the lost motion connection between theinterlock and swltch actuating element. The electromagnet of theinterlocking mechanism will be supplied with suflicient energy to holdthis armature retracted until the speed of the motor has been reduced tosuch an extent that the voltage across the armature is practically zero.

Should a contactor stick, when an attempt was being made to effectreversal of the motor, the lock plunger would not be withdrawn, becausethe line current flowing would flow in part through the 001i 40 andprevent movement of the reverse switch to reverse position. If the motoris not running at a sufficient speed so that the counter electro-motiveforce would hold the lock in, no detriment would result from reversing.

While I have in thisapplication specifically described one form whichthe invention may assume in practice, it will be understood thatthis-form is shown for purposes of illustration and that the inventionmay be moditied and embodied in various other forms without departingfrom its spirit or the scope of the appended claims. 7

W hat I claim as new'and desire to secure by Letters Patent is:

1. In combination, a motor, a controlling device therefor, reversingmechanism for controlling direction of rotation of said m0- tor, meansoperated on-movement of said reversing mechanism for controlling saldcontrolling device, and means for preventing movement of said reversingmechanism sufiicient'to efiect reversal of said motor until the motorhas come substantially to a standstill'but permitting enough movement toeffect control of said controlling device.

2. In combination, an electric motor, controlling apparatus therefor, areverse switch for controlling directionof rotation of said motor, meansoperated directly by movement of said reverse switch for controllingsaid controlling apparatus, and means for preventing movement of saidreverse switch sufficient to reverse current flow in said motor whilethe motor is rotating but'permitting enough movement to effect controlof's aid controlling apparatus.

3. In combination, an electric motor, controlling means therefor, areverse switch for controlling direction of rotation ofsaid mo tor,means operated on movement of said reverse switch for controlling saidcontrolling means, and a positivelocking device for preventing movementof said reverse switch to a position effecting reversal of current flowin said motor while the motor is rotating at a substantial speed butpermitting movement to eifect control of said controlling means wherebythe voltage which may be applied to the motor on reversal is materiallyreduced.

4. In combination, an electric motor, automatic controlling apparatustherefor, a reverse switch for controlling direction of rotation of saidmotor,'a control switch operated on movement of said reverse switch ineither direction from a neutral position for controlling saidcontrolling apparatus, and means for preventing movement of said reverseswitch. to a position effecting reversal of current flow in'said motorwhile'th'e motor is rotating above a certain speed but permitting enoughmovement to effect 'operation of said control switch.

5. In combination,a source'of power, a resistance, an electric motor,controlling apparatus for said motor for connecting the same to thesource of power and for interrupting power supply including means forconnecting the motor to the source of power through the resistance andautomatically gradually cutting out said resistance, a reverse switchfor controlling direction of rotation of said motor, a control circuitfor controlling said controlling apparatus provided with a pilot switch,means automatically operating said pilot switch on predeterminedmovement of said reverse switch, and means for preventing movement ofsaid reverse switch to a position effecting reversal of current in saidmotor while the motor is rotating at a predetermined speed butpermitting movement of the reverse switch to efiect control of saidpilot switch and controlling apparatus.

6. In combination, an electric motor, automatic controlling apparatustherefor, a reverse switch for controlling direction of rotation of saidmotor,.a pilot circuit controlling said controlling apparatus, a pilotswitch in said circuit automatically operated on V movement of-saidreverse switch from neutral 'posltlon to eitherof its on positions forsetbreak the connections established thereby while the motor has motionabove a predetermined speed, and means for energizing saidelectromagnetic means directly across the armature terminals of saidmotor.

8. In an electric motor controlling apparatus, a motor, a manuallyoperable reverse switch lei efi'ecting reversal oi said motor, amechanical interlocking mechanism for preventing movement of saidreverse switch from one direction controlling position to another or tobreak the circuit therethrough but permitting a limited movement of saidreverse switch, electromagnetic means for actuating said interlockingmechanism to interlocking position when energized, and a circuitconnected directly across the armature terminals for energiang saidelectromagnetic means.

9. In an electric motor system, a source of power, a resistance, amotor, controlling apparatus for connecting the same to the source ofpower and for interrupting power supply including means for connectingsaid motor across the line through the resistance and automaticallygradually cutting out said resistance, a pilot circuit for setting saidautomatic apparatus into operation provided with a pilot switch, amanually operable reverse switch for controlling said pilot switch anddirection of rotation of said motor, interlocking mechanism allowingmovement of the reverse switch to effect control of said pilot switchbut preventing movement from one direction controlling position to theother while the motor is rotating at a substantial speed, anelcctromagnet for rendering said interlocking mechanism effective whenenergized, and a circuit for energizing said electromagnet by currentflow through said armature.

10. In combination, an electric motor, controlling apparatus therefor, apilot switch for controlling said controlling apparatus, reverse switchmeans for controlling direction of rotation of said motor, a commonoperating element for said pilot switch and said reverse switch means,and interlocking mechanism for preventing movement of said operatingelement to a position effecting reversal of current flow in said motorwhile the motor is rotating at a substantial speed but permittingmovement to efiect operation of said pilot switch.

11. The combination specified in claim 10 wherein said interlockingmechanism comprises a plurality of elongated recesses in said element, aplunger adapted to engage in either of said recesses to permit only alimited movement of said operating element, and an electromagnet foractuating said plunger to interlocking position energized by voltageacross the armature terminals.

12. In combination, an electric motor, controlling apparatus therefor, apilot circuit for said controlling apparatus, a pilot switch in saidcircuit, reverse switch means for controlling direction of rotation ofsaid motor, a common operating element for said pilot switch and saidreverse switch means, interlocking mechanism for permitting movement ofsaid operating element suliicient to control said pilot switch butpreventing suflicient i'novcmen to reverse current flow in the motorvhile rotating at a substantial speed, electromagnetic means foroperating said interlocking mechanism to eiiectiveposition, and meansfor controlling said electromagnetic means in response to voltagegenerated in the armature during rotation.

13. In an electric motor controlling apparatus, a reversible motor, amanually operable reverse switch, electromagnetic interlocking means forpreventing movement of the reverse switch from one direction controllingposition to the other while the motor has motion above a predeterminedspeed, means for energizing said electromagnetic means by voltage acrossthe armature terminals during motor rotation, and means for preventingimmediate reversing by said reverse switch after release of saidinterlocking means.

14. In combination, a reversible electric motor, controlling apparatustherefor, a pilot switch for controlling said controlling apparatus, areverse switch for controlling direction of rotation of said motor,common operating means for said pilot switch and reverse switch,interlocking mechanism for preventing operation of said reverse switchirom one direction controllin position to the other while permittingoperation of said pilot switch while the motor has motion above apredetermined speed, electromagnetic means for controlling saidinterlocking mechanism in response to voltage across the armatureterminals, and mechanical means cooperating with said common operatingmeans for preventing uninterrupted movement of said reverse switchat'ter release of said interlocking mechanism.

15. In combination, an electric motor, controlling apparatus theret'or,a pilot switch for controlling said controlling apparatus, reverseswitch means for controlling direction of rotation of said motorincluding relatively movable contacts, a. common operating element forsaid pilot switch and said reverse switch means operable to operate saidpilot switch only subsequent to movement of said reverse switch to acircuit establishing position, and interlocking mechanism for preventingmovement of said operating element to effect breaking of a circuit atthe reverse switch contacts while the motor is rotating at a substantialspeed but permitting movement or" said operating element to effectrestoration of said pilot switch to its initial position.

16. A motor, lines for supplying current thereto, a switch movable toeiiect a predetermined relation. between the terminals of the motor toprepare the same for rotation in a predetermined direction on linecurrent supply thereto, a switch movable to establish and to'interruptflow of line current to said motor,- means movable to operate said firstmentioned switch and thereafter said second mentioned switch andreversely movable to effect their opening in reverse order, and meansfor preventing reverse movement of said first mentioned means to effectopening of said first mentioned switch while said motor is'rotatingabove a predetermined speed but permitting movement thereof'to etl ectopening of said second mentioned switch.

17. In combination, a motor, a switch closed to effect motor operationand opened to stop the motor, a reversing switch, and common operatingmeans for said switches having a neutral position and movable inopposite directions therefrom and operative on predetermined movementsin opposite directions from said neutral position to move said reversingswitch to its positions for establishing circuits to efiect operation ofsaidmotor in opposite directions and on further predetermined movementsfrom said. neutral position in either direction to effect closure ofsaid'first mentioned switch, and means for controlling movements of saidoperating means towards neutral position preventing movement of saidreversing switch to break circuits established by its movement fromneutral position while said motor is rotating at a rate above apredetermined speed.

18'. In' combination, a motor, a switch closedto efiectmotor operationand opened to stop the motor, a reversing switch, and com mon operatingmeans for said switches having a neutral position and movable inopposite directions therefrom and operative on predetermined movementsin opposite directions from said neutral position to move said reversingswitch to its positions for establishing circuits to effect operation ofsaid motor in opposite directions and on further predetermined movementsfrom said neutral position in either direction to effect closure of saidfirst mentioned switch, and means for controlling movements of saidoperating means towards neutral position preventing movement of saidreversing switch to break circuits established by its movement fromneutral position while said motor is rotating at a rate above apredetermined speed including electro-magnetically controlied lockingmeans supplied with current whenever the motor is rotating above apredetermined speed.

In testimony whereof I afiix my signature.

CHARLES W. WYMAN.

